Options
Faults Geometry and the Role of Fluids in the 2016-2017 Central Italy Seismic Sequence
Author(s)
Language
English
Obiettivo Specifico
Status
Published
JCR Journal
JCR Journal
Title of the book
Issue/vol(year)
/45(2018)
Pages (printed)
6963-6971
Issued date
2018
Abstract
The 2016–2017 Central Italy seismic sequence ruptured overlapping normal faults of the
Apennines mountain chain, in nine earthquakes with magnitude Mw > 5 within a few months. Here we
investigate the structure of the fault system using an extensive aftershock data set, from joint permanent and
temporary seismic networks, and 3-D Vp and Vp/Vs velocity models. We show that mainshocks nucleated on
gently west dipping planes that we interpret as inverted steep ramps inherited from the late Pliocene
compression. The two large shocks, the 24 August, Mw = 6.0 Amatrice and the 30 October, Mw = 6.5 Norcia
occurred on distinct faults reactivated by high pore pressure at the footwall, as indicated by positive Vp/Vs
anomalies. The lateral extent of the overpressurized volume includes the fault patch of the Norcia
earthquake. The irregular geometry of normal faults together with the reactivated ramps leads to the
kinematic complexity observed during the coseismic ruptures and the spatial distribution of aftershocks.
Apennines mountain chain, in nine earthquakes with magnitude Mw > 5 within a few months. Here we
investigate the structure of the fault system using an extensive aftershock data set, from joint permanent and
temporary seismic networks, and 3-D Vp and Vp/Vs velocity models. We show that mainshocks nucleated on
gently west dipping planes that we interpret as inverted steep ramps inherited from the late Pliocene
compression. The two large shocks, the 24 August, Mw = 6.0 Amatrice and the 30 October, Mw = 6.5 Norcia
occurred on distinct faults reactivated by high pore pressure at the footwall, as indicated by positive Vp/Vs
anomalies. The lateral extent of the overpressurized volume includes the fault patch of the Norcia
earthquake. The irregular geometry of normal faults together with the reactivated ramps leads to the
kinematic complexity observed during the coseismic ruptures and the spatial distribution of aftershocks.
Type
article
File(s)
Loading...
Name
2018GL077485.pdf
Size
4.27 MB
Format
Adobe PDF
Checksum (MD5)
42c947585e280daace6fa43e6b6c8b13